The proposed research project involves the regulation of the biogenesis of the methylated derivatives of indoleamines in the brain; (1) To attempt the in vitro synthesis of 5-methoxy-N,N-dimethyl-tryptamine (5-MeO-DMT) and related compounds in rat brain tissue using S-adenosylmethionine (SAM) as the methyl donor. (2) To demonstrate the presence of hydroxyindole-O-methyltransferase (HIOMT) in the hypothalamus and other areas of the brain. (3) To follow the enzymatic formation of methylated indoleamines in response to the treatments of amphetamine, methionine, and monoamine oxidase inhibitor (MAOI). (4) To determine the activities of these enzymes - monoamine oxidase, hydroxyindole-O-methyltransferase and indoleamine-N-methyltransferase (NMT) in normal controls and experimental rats and correlate their ability to catalyze the formation of the psychotomimetric methylated indoleamines. (5) Biosynthesis products will be characterized by thin layer chromatographic procedures, carrier crystallization techniques and mass spectrometric analysis.